Richard Reeves, a Brookings Institution economist, has made a brief video using Legos to visualize the hard facts about getting ahead in the U.S. "In terms of fairness," he says, the question is less about the income gap between the bottom and top and "more about your chance of making it from the bottom to the top."

Right now, for people born on the bottom, more than one in three of them will remain stuck there and just one in 10 are going make it all the way to the top. Follow the movements of the Lego minifigures, as Reeves shows how those numbers change, depending on whether you're white, black, college educated, a high school dropout or the child of a single parent.